Vapor generator



Aug., i3, 1946. FRlscH 294955732' I VAPOR GENERATOR f Filed Nov. l2, 1941 2 Sheets-Sheet l Aug. E3, 1946. M. FRlsczl-nv VAPOR GENERATOR FiledNov. 12,'1941 2 Sheets-SheetZ /N VEA/TOR A TTORNE Patented Aug. 13, 1946 VAPOR GENERATOR Martin Frisch, New York, N. Y.,"assignor to Foster l*Wheeler Corporation, New York, N. Y., a corporation of New York Application November 12, 1941, Serial No. 418,650 43 Claims. (Cl. 122-7448) This invention relates to vapor generators and more particularly pertains to vapor generators of the forced circulation type.

As applied to the generation of steam, the invention provides a forced circulation steam generator in which the amount of Water storage is reduced to a minimum by dispensing with the drum or other usual type of VVessel in which separation of the steam from the circulating water is effected, and replacing it with a separator of small volume in which the water and steam are separated mechanically by rapid rotation of the separating device which is operative with the circulating pump.

In the preferred arrangement, the ycirculating pump is driven, after the generator is started, by the steam owing from the separator. To assure immediate and adequate circulation when the generator is started, an auxiliary water turbine is utilized to drive the circulating pump by feed water which is returned to the suction of the feed pump or to some intermediate stage thereof. Glands or external bearings are not required because cooled feed water at full feed pump pressure is employed to provide lubrication for the internal bearings of the pump and separator.

The generator may be controlled manually in the same manner as a natural circulation steam generator is controlled, or it may be controlled automatically. I n the form of the invention disclosed, the generator is controlled automatically. One feature of this -control is the regulation of the amount of water passed through the auxiliary water turbine and the amount of steam passed through the steam turbine so as to maintain a predetermined rate of circulation at all loads on the generator. A differential across a flow nozzle in the circulating water line actuates flow controllers which govern the flow of water to the auxiliary water turbine and the flow of steam to the steam turbine. The ow controllers are set so that as the load increases, the amount of water flowing through the water turbine is decreased progressively and the flow of steam through the steam turbine is increased progressively, so that at full generator load only sufiicient water is passed through the water turbine to prevent boiling due to churning.

The tubes of the steam generating and the superheating sections are so arranged that there are a plurality of main paths of flow from the inlet to the outlet of each section, with the lengths ofthe Vflow paths in each section substantially equal and with'the flow through each section and each path of each section generally concurrent to the flow of gases.

'Ihe invention will be understood from the following description when considered in connection with the accompanying drawings forming a part thereof, and in which:

Fig. 1 is a vertical sectional View, more or less diagrammatic, of a forced recirculation steam generator embodying the invention;

Fig. 2 is an enlarged vertical sectional view of the upper portion of the separating and circulating device shown in elevation in Fig. l, and

Fig. 3 is a vertical sectional view of the lower portion of the separating and circulating device.

Like characters of reference refer to like parts throughout the several views.

Referring to Fig. 1, the` setting of the generator shown, has opposite side walls I I and I2, a roof I3, and a gas outlet I4. An economizer I5 in the outlet Isis connected to a feed water conduit lileading from the discharge side I'I of a feed pump I8 which is driven by a motor I9 connected to a source of electricity, not shown. Feed water enters the pump I8 at the suction side 20 thereof, and is forced through conduit I6 and through the economizer I5 in a direction of ow counter-current to the direction of flow of the heating gases into an outlet conduit 2I which is connected to a separating and circulating device 22. As shown, the separating and circulating device comprises an elongated, vertically disposed, housing 23 having a fluid chamber 24 therein and a circulating pump casing 25 at the bottom of the housing.

The lower end of the chamber 24 is connected Y by a passage 28 with -a chamber 29 in the casing. The lower end of the casing 25 is Iclosed by a cap 30 having a hollow extension 3|. Cap 39 has an annular flange 32 which projects into the chamber 29, and engages a partition 33 holding it tightly against an annular shoulder 34 to divide the chamber 29 into two separate chambers, a circulating pump chamber 35, and a water turbine chamber 36. A drive shaft 31 having a reduced lower end portion 38 rotatably mounted in a thrust bearing 39 is disposed in the closed end of the cap 3l in fluid-tight relationship thereto, and extends through the chambers 24, 35 and 36. The shaft 3l is hollow throughout the greater part of its length with solid end portions, but it may be solid throughout the entire length thereof, if desired.

A water turbine 4I having blades 42 which extend into the cap 3l is fixed to shaft 31 in chamber 33. Chamber 36 has an inlet port 43 in communication with the discharge side I1 of the feed pump I8 through conduit I6 and a conduit 44, and an outlet conduit 45 conducts water from the chamber to the suction side of the feed pump A circulating pump impeller 46 is fixed to the shaft 3l above the water turbine and in the chamber 35. The impeller 45 has a plurality of blades 45 which are curved downwardly and outwardly from the passage 28 to the periphery of the impeller. Feed water flows into the impeller from the chamber 24 and is discharged into a feed conduit 52 which conducts circulating water to the steam generating section of the generator. i

As shown, the tubes of the steam generating section are arranged to provide two main paths of flow in parallel, from the inlet header 53 to the outlet header G. One main path comprises tubes 55 which are connected to a fitting 55 having communication with the inlet header 53, and which extend vertically upwardly in a single row at about the center of the setting and then extend horizontally toward the wall ll to define one side and the top of a boiler furnace 5'l. Thereafter the tubes 55 extend in a plurality of superposed and horizontal rows over the boiler furnace and in a plurality of additional superposed and horizontal rows substantially entirely across the setting to the outlet tting 58 which is connected to the outlet header 54. The other main path comprises tubes 59 which extend from the inlet fitting 56 horizontally along the bottom of the boiler furnace 51 in a single row and then vertically upwardly in a single row along the wall ll to a point above the first two horizontal rowsv of the tubes 55, after which they extend in a plurality of superposed and horizontal rows above the boiler furnace and thereafter in like manner sub stantially entirely across the setting to the outlet fitting 58. The tubes in the horizontal rows above the boiler furnace are staggered, that is, with the tubes in alternate rows at a different elevation as compared with the elevation of the tubes in the other rows. i

The tubes ofthe superheating section are arranged similarly to those of the steam generating section excepting that they do not extend entirely across the setting. The superheater inlet header G0 adjacent the inlet header 53 is connected to an inlet fitting Si to which the superheater tubes of both main paths are connected. Tubes 52 extend vertically upward ina single row adjacent the tubes 55 to the elevation of the lowermost horizontal row of tubes 55, and then turn and extend horizontally to the wall I2 of the setting to define one side and the top of a superheater furnace B4. Thereafter, the tubes 52 extend in-a plurality of superposed and horizontal rows to an outlet fitting 65 which is connected to a. superheater outlet header 55 from which the superheated steam flows to the point of use through a conduit El. Tubes 63 extend along the bottom and a side of the superheater furnace and in a plurality of superposed and horizontal rows to the outlet fitting 65. The horizontal rows of the superheater tubes are staggered in the same manner the tubes of the horizontal rows of the steam generating section are staggered.

The rear wall of both furnaces 51 and 64 are lined with water tubes, not shown, which vare connected in the circulatory system so as to be supplied with water from header 53 and to deliver fluid tothe outlet header 54.

With this arrangement of the tubes of the 4 steam generating and superheating sections, the paths of flow through the tubes 55 and 59 are substantially equal and the paths of flow through the tubes 62 and E3 are also substantially equal, with the flow through each of these groups of tubes generally in the direction of flow of the gases of combustion.

The boiler and superheater furnaces are separately red, the gases produced in the boiler furnace 51 flowing through the furnace and over the horizontal rows of tubes 55 and 59 to the outlet I4 and over the economizer l5 therein. The gases produced in the superheater furnace t now through the furnace and over the horizontal rows of the tubes 62 and 63 and then over the horizontal rows of tubes 55 and 5S of the steam generating section and to the outlet ifi. The tubes 55 and 62 are arranged, with or without other wall or baffle means, to prevent the flow of gases from one furnace to the other.

The mixture of steam and water discharged from the steam generating section is conducted by a conduit 68 to the upper part 69 of the separating and circulating device 22, and is delivered tangentially into a separating chamber l0 therein which communicates at its lower end with the upper part of chamber 24 in the housing 23. A tubular member 'll of lesser diameter than the chamber 1l] and having a passage l2 therein is disposed in the chamber 1D, and as shown, is provided with a peripheral flange 'I4 which is received in a recess in part 63 to support the tubular member in position. A mechanical steam and water separator 81, Fig. 2, is provided as shown, by'a plurality of radial blades 98, fixed to shaft 3'! in chamber 10 closely adjacent the lower end of the tubular member 1I in the path of steam flowing from the separating chamber 1Q. Other forms of separators may be employed. The tubular member 'il projects upwardly into a` hollow cap 15 which closes the upper end of part 59, to a point short of the upper end thereof, thereby forming a space 'f5 between the end of the tubular member and the cap. A cylindrical member ll is secured at its upper end to the upper end of member l! and extends downwardly in the mern ber 'Il in spaced relationship to the inner wall thereof to provide an annular steam by--pass passage 13. The interior of member 'il provides a main steam passage 13, which communicates with the space 15, for steam flowing from the passage '52. A plurality of spaced stationary turbine blades 29 disposed at the lower end of the member 'l, and a plurality of rotatable blades 8! fixed to shaft 31 above the blades 'E9 provide a steam turbine Si which is operated by steam flowing from passage 'l2 into passage 78. A steam conduit 82 which conducts steam from the separating device to the inlet header 550i the superheater, is connected at its inlet end to the space l5 through a branch conduit 83 and to passage 7.2 through a by-pass conduit 84, the conduits 83 and S4 being controlled by a slide valve 85 which is actuated by a pressure responsive device 86, Fig. 1.

The upper end of drive shaft 3'! extends through the passages 'I2 and 'I8 and is rotatably mounted in a thrust bearing 83 in a projection 89 on cap 15. A housing Si) forms a chamber 9i around the bearing 88 and the shaft 3'1. Bearing 83 is cooled by feed water from a heat exchanger 92, Fig. 1, which is conducted to the bearing through a conduit 93. Bearing 39 at the lower end of the shaft 37 is cooled also by feed water from heat exchanger S2 conducted to the bearing through conduits 93 and 94. Water is withdrawn from chamber 9| through a conduit 95 controlled by a valve 95'. Shaft 31 is also supported above the circulating pump 46 in a bearing to Which cooled feed Water for lubrication is supplied by conduit 96. The feed Water supplied to the bearings 39 and 40 after lubricating these bearings, mixes with the Water discharged from the auxiliary turbine and the Water discharged by the circulating pump, respectively. Heat exchanger 92 is connected to feed water conduit I6 through a conduit 93' and a cooling medium is supplied thereto through a conduit 92 and is Withdrawn therefrom through a conduit 92".

A trap H6, Fig. 3, is secured in the lower portion of the chamber 24 above the point at which the Veconomizer outlet conduit 2| is connected to the housing 23. The trap is shaped to provide a 'passage around the shaft 31 through which Water will ow from chamber 24 into the passage 28 and the circulating pump 46. A blow-*down conduit ||1 connects with the bottom of the trap and is controlled by a valve i8.

The quantity of Water delivered to the auxiliary water turbine and the quantity of steam flowing to the steam-turbine is varied in response to variations in the quantity of Water delivered to the steam generating section by the circulating pump. To this end, a flow nozzle 0|, Fig, l, is positioned in the feed Water conduit 52 and pressure conduits |02 and |03 connect opposite sides of the nozzle In! with opposite sides of the diaphragm of a pressure responsive device |04 which controls the flow of Water in the outlet conduit through a valve |05. C'onduits |66 and |01 connect opposite sides 0f the diaphragm of pressure responsive device 66 with the conduits |02 and |03 respectively. The pressure responsive devices |04 and 86 are so arranged that an increase in the flow of circulating water through the conduit 52 Will cause the device |04 to operate the valve |05 to decrease the flow of water through conduit 45 and to the auxiliary Water turbine, and at the same time to cause the device 86 to operate the valve 85 to decrease the flow of vapor through the by-pass conduit 84 thereby increasing the iiow through the branch conduit 83 and to the steam turbine. A decrease in the flow of circulating Water through the conduit 52 Will have the opposite eiect.

The quantity of feed Water is regulated in response to the rate of steaming. To accomplish this, a flow nozzle |08, Fig. l, is positioned in the steam conduit 82 and opposite sides of this orifice are connected by conduits |09 and ||0 to opposite sides of the diaphragm of a pressure responsive device which operates a valve ||2 in conduit I6 to control the flow of feed Water to the economizer |5. An increase in the flow of steam through the conduit 82 will cause the device to actuate valve ||2 to permit an increase in the ow of Water to the economizer, and vice versa, a decrease in the flow in the conduit 82 will cause a decrease in the flow of Water to the economizer.

Valve ||2 is .also actuated independently of the pressure responsive device to regulate the level of Water to the chamber 24 of the separating and circulating device 22, irrespective of variations in the rate of steaming. This is accomplished by an auxiliary feed control pressure responsive dLevice ||3 which is in communication with a liquid level .controller ||4 through a tube 5. The level controller H4, which is of the vapor pressure type, has a control tube I6 therein which communicates With the chamber 24 at points above and below the normal Water level therein. As the Water in chamber 24 rises to a predetermined level, the device ||3 actuates the valve ||2 to decrease the fiow of water to the economizer I5 through conduit I6 and to the chamber 24, and when the Water falls .below the predetermined level, the valve is actuated to permit an increased flow of Water to the economizer and the chamber 24.

IThe boiler furnace 51 is fired by a fuel burner |24 to Which fuel is supplied through a `fuel line |26, while the superheater furnace 64 is fired by a fuel burner |25 to which fuel is supplied through fuel lines |26 and |21. Positioned in the fuel line |26 between the source of fuel supply and the burners |24 and |25, is Aa control valve |28 actuated by a pressure responsive device |29 which operates in response to the pressure in the superheater steam outlet conduit 61 and is connected thereto through a tube |30. Valve |28 is actuated to permit an increased flow of fuel to the burners when the vapor pressure in the conduit 61 decreases and to decrease the oW of fuel to the burners when the vapor pressure in the conduit 61 increases. A control valve |3| similar to valve |28, controls the feed conduit |21. Valve |3| is operated by an actuating device |32 Which is responsive to the temperature in the superheater vapor outlet 61 and is connected thereto through a line |33. Upon an increase in temperature in the conduit 61, the valve V|3| is actuated to decrease the flow of fuel to the burner |25 and upon a decrease in temperature, the

, valve permits an increased flow of fuel to the burner.

An orifice |34`is disposed in the fuel line |26 between the valve |28 and thek source of fuel supply. Opposite sides of the orice are connected through lines |35 and |36 to a pressure responsive actuating device |31, which operates through a rack and pinion mechanism, a damper |39 in an air conduit |40 Which conducts air to the burners |24 and |25. A branch conduit |4| connects the conduit |40 with the burner |24. The arrangement is such that an increase in the iiow of fuel lto the burners through line |26, Will cause the pressure device |31 to actuate th'e damper |39 to permit an increased flow of air to the burners, while a decrease in the flow 0f fuel in line |26, will cause the damper |39 to be actuated to decrease the flow of air to the burners. An auxiliary pressure responsive device |4| is connected to opposite sides of an Orifice |42 in air conduit v|40 by tubes |43 and |44, and operates in conjunction With the device |31 to control the damper |30.

An orice |45 in the fuel line |21 to the superheater burner |25, has its opposite sides connected to a pressure responsive device |43 which' actuates through rack and pinion mechanism, a damper |49 in the air conduit |40 to increase and decrease the quantity of air flowing to the burner |25 in response to variations in the flow of fuel to the burner, an increase in the iiow of fuel causing the damper to move to a more open position to permit a greater quantity of air to flow to the burner, While a decrease in the flow 0f fuel will cause ithe damper to move to a more closed position to decrease th'e quantity of air delivered to the burner. An auxiliary pressure responsive device |50 is connected across an orifice |5| in the conduit |40 and operates in conjunction with the device 48 to control the damper |49.

The means for controlling .the supply of fuel and air to the burners 24 and |25 operates automatically to supply air and fuel to each burner in the proper'amount to maintain the desired rate of steamV generation. vIf the desired rate is exeeeded, Ithe control means will operate automatically to causeV a decrease in the supply of fuel and air to the burners, whereas if the desired rate is not attained, the fuel and air supply to the burners will be increased. In addition to this control of both burners in response to rthe final pressure of the steam, the superheater burner is controlled to obtain or to maintain the desired final temperature of the steam by increasing anddecreasing the supply of fuel andair to the superheater burner as the steam temperature decreases and increases respectively. Th'e amount of fuel and air supplied to the burners may be controlled manually, or by automatic means other than that disclosed, if desired.

In operation, feed water is forced through conduit IS by feed pump i8 into and through the economizer |5 and conduit 2| into the lower part of chamber 24 of the separating and circulating device. Simultaneously,4 feed water is forced through conduit 44 and over the auxiliary water turbine 4| to rotate the shaft 3l' and the circulating pump 46. Water discharged by the turbine 4| flows'through conduit 45 and is returned to the pump I8 through fully open valve |05.

Heated feed water delivered into the chamber 24 through conduit 2|, flows downwardly to the circulating pump 46 which forces it through' conduit 5 2 into and through the tubes 55 and 59 of the steam generating section 0f the generator.

The steam generated together with unvapo-rized water flows through conduit 58 into the chamber V'lil of the separating and circulating device and flows in a spiral path through the chamber, causing the water and solids entrained in the steam to be separated from the steam. The separated water and solids flow down into the chamber 24 where the separated solids are deposited in the trap |G and are removed th'rough the blow-down valve H8. The water flows into the water in the lower part of chamber 24 and is recirculated through the tubes of the steam generating section by the pump with the heated feed water from the economizer. The separated steam in chamber T0, flows over Athe rotating blades 88 which effects a further separation of water and entrained solids from the steam, and

thereafter flows upwardly through passage 12.

Depending upon the position of valve 85, the steam in passage 12 will iiow through passage 73 and by-pass 84, or it will iiow to the steam turbine and through passage 'I3 and passage 83, or through' both these paths of flow. When the generator is started up, valve 85 is positioned to permit maximum ow of vapor through the bypass 8:1 inasmuch as the circulating pump is being driven by Athe water turbine. Flow of steam from passage 12 into passage 'I8 drives turbine 8D and the shaft 37. The steam flowing through passage 83, Icy-pass 84, or both, flows through conduit 82 into and through the tubes of the superheater and through conduit E1 to the point of use.

Steam flowing into passage 18 will rotate the turbine 8| and the shaft 3l at a greater speed than that at which the shaft is driven by the water turbine 4|, so that as soon as steam is produced in suiiicient quantity to drive th'e shaft 31 by the turbine 8|, the speed of shaft 31 will increase and the circulating pump 46 will be driven faster and circulating water will be forced into and through the conduit 52 and the steam generating section at a higher velocity than when the circulating pump is driven by the water turbine. This increase in the flow of Water through the conduit 52 and the ilow nozzle I|l| therein causes the device |94 to move the valve |05 in line 45 toward closed position, thereby reducing the quantityof water delivered to the water turbine 4|. Simultaneously, the pressure responsive device 86 actuates the valve 85 to decrease the iiow of steam through the by-pass conduit 84 and to increase the flow of steam to the steam turbine 8|, thereby increasing the speed of rotation of the shaft 3l and the circulating pump t6. Consef quently, as the load and the rate of evaporation increases, the quantity of steam delivered to the steam turbine progressively increases rand the quantity of water delivered to the water turbine progressively decreases, until at maximum load `the quantity of water delivered to the water turbine is sufficient only to provide substantially the minimum circulation in th'e water turbine chamber 36 to prevent boiling due to the churning of the water therein resulting from the rotation of the water turbine.

As the angular velocity of the shaft 31 increases because of a greater iiow of steam to the steam turbine, valve ||2 in feed line le to the economizer is operated to increase the now of water circulated by the circulating pump and, through the flow nozzle I6 l, pressure responsive device |04 and valve |135, to decrease the now to the water turbine, and vice versa, with the result that in starting the generator, the water turbine drives the circulating pump and after starting, the separated saturated steam drives the circulating pump. Specically, when the generator is started up, the valve H2 is in a position to permit the minimum required circulation of water through the steam generating section, but as the rate of steaming increases, pressure responsive device il operates to move valve |42 toward open position to increase the circulation, until at the maximum rate of evaporation, valve I| 2 is nearly fully open. Contrariwise, a drop in load will cause valve H2 to move toward closed position to decrease the circulation through the steam generating section. Valve i l2 also functions in response to thedevice H3 to maintain the desired water level in the chamber 24 of the separating and circulating device 22. If the level drops, valve ||2 will open to increase the circulation through the economizer and the quantity of water delivered to the lower partv of chamber 24, while if the level is raised, valve ||2 will move toward closed position to decrease the flow of water into the chamber 24.

Withv this arrangement and operation, it will be perceived that a separator of small volume having mechanical separating means is employed in lieu of the usual drum or equivalent device, with the advantage that the amount of water storage is reduced to a minimum. The unitary arrangement disclosed of the glandless circulatlng pump, mechanical separator, feed water turbine and steam turbine drive, is compact and efficient. The operating cycle and the control system are effective to control the operation at all loads on the generator so as to maintain a predetermined output at all loads. Adequate circulation is provided at all times including immediate circulation when the generatpr is started up, by utilizing part of the feed water to operate the circulating pump until the rate of steam generation is adequate to operate the pump by steam.

Although the invention is disclosed in connection with a forced recirculation steam generator, it is applicable also to other types including once through generators.

It will be understood that the form of the invention disclosed is a preferred form and that changes may be made in the form, location and relative arrangement of the several parts of the apparatus disclosed, as Well as in the method steps and their sequence without departing from the principles of the invention. Accordingly, the k invention is not to be limited excepting by the scope of the appended claims.

What is claimed is:

1. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid in said path for conversion of liquid to vapor, means for actuating said circulating means by vapor flowing from said path, fluid driven auxiliary actuating means for Said circulating means, and fluid feeding means for supplying fluid under pressure to said auxiliary actuating means, the discharge of the driving means being unconnected directly with the inlet of the circulating means.

2. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for driving said circulating means by vapor flowing from said path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, and control means to control the flow of fluid to said auxiliary driving means in response to the flow of fluid to said path.

3. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid into said path under pressure, means for heating the fluid for conversion of liquid to vapor, separating means in said path for separating moisture from vapor, vapor actuated driving means for driving said circulating means by vapor flowing from said separating means, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, and control means responsive to the flow of fluid from said circulating means for controlling the flow of fluid to said auxiliary driving means and the flow of vapor to said vapor actuated driving means to diminish the flow of fluid to said auxiliary driving means and to increase the flow of vapor to said vapor :actuated driving means upon an increase in flow of fluid from said circulating means.

4. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, mean-s for delivering fluid to the circulating means, driving means for the circulating' means actuated by vapor discharged from said flow path, means for conducting vapor from said path to said driving means, means forming a discharge passage for vapor flowing from said driving means, means forming a by-pass for vapor around said driving means, valve means for controlling both said discharge passage and said bypass to control the quantity of vapor delivered to said driving means, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, and means for rendering said auxiliary actuating means inoperative and formoving said valve to control the by-pass when the circulating means is actuated by the vapor actuating means and for rendering the auxiliary driving means operative and for moving said valve to control the discharge passage when the circulating means is not actuated by said vapor actuated means.

5. A vapor generator comprising a vapor generating section, and separating and circulating means comprising a housing, a circulating pump in the housing, a vapor and liquid separator in the housing, a Vapor actuated turbine in the housing for driving the circulating pump, a fluid actuated means in the housing constituting auxiliary means for driving the circulating pump, and control means for rendering the fluid actuated means inoperative when the circulating pump is actuated by the vapor actuated turbine and for rendering the fluid actuated means operative when the circulating pump is not actuated by said vapor actuated turbine.

6. A vapor generator comprising a vapor generating section, and separating and circulating means comprising a housing, a circulating pump in the housing, a vapor and liquid separator in the housing, a vapor actuated turbine in the housing for driving the circulating pump, movable separating means in the housing operable with the circulating pump, fluid actuated means in the housing constituting auxiliary means for driving the circulating pump, and control means for rendering the fluid actuated means inoperative when the circulating pump is actuated by the vapor actuated turbine and for rendering the 'Y fluid actuated means operative when the circulating pump is not actuated by said vapor actuated turbine.

7. A vapor generator comprising a vapor generating section, and separating and circulating means comprising a housing, a shaft rotatable about its axis in the housing, a centrifugal circulating pump on said shaft and rotatable therewith, a vapor and liquid separator in the housing, a vapor actuated turbine on said shaft oper- Y able by vapor flowing from said separator for driving the shaft, fluid actuated means on said shaft operable as auxiliary driving means for said shaft, and control means for-rendering the fluid actuated means inoperative when the circulating pump is actuated by the vapor actuated turbine and for rendering the fluid actuated means operative when the circulating pump is no-t actuated by said vapor -actuatedturbine 8. A vapor generator comprising a vapor generating section, a superheating section, means for firing the vapor generating and superheating sections, an cconomizer, a feed pump for delivering fluid to the economizer, a circulating pump, conduit means for conducting heated fluid from the economizer to the circulating pump, conduit means for conducting fluid under pressure from the circulating pump to the steam generating section, a separator, means for conducting vapor and fluid from the steam generating section to the separator, a vapor turbine in the path of vapor flowing from the separator and constituting main driving means for the circulating pump, a fluid actuated wheel constituting auxiliary driving means for the circulating pump, means for conducting fluid from the feed pump tothe fluid actuated wheel, means for conducting fluid from said wheel to the suction of the feed pump, means i the superheating section, means responsive to the ilowV of fluid from the circulating pump to the vapor generating section for controlling the Yow of fluid from the feed pump to said iluid actuated wheel, means forming a by-pass for vapor around said vapor turbine, means responsive to the flow of fluid from the circulating pump to the vapor generating section for controlling said by-pass to control the flow of vapor to said vapor turbine, and means responsive to the flow of vapor from said vapor turbine to said superheating section for controlling the flow of fluid from the feed pump to the economizer.

9. A vapor generator comp-rising a vapor generating section, andseparating and circulating means comprising a housing, a shaft rotatable about its axis in the housing, a centrifugal circulating pump cn said shaft and rotatable therewith, a vapor and liquid separator in the housing, a vapor actuated turbine on said shaft operable by vapor flowing from said separator for driving the shaft, a fluid actuated wheel on said shaft operable as auxiliary driving means for said shaft, a feed pump for delivering fluid to the circulating pump to be delivered tc the vapor generating section, bearings in said housing for said shaft, and means for conducting fluid from the feed pump to said bearings to lubricate the bearings.

10. A vapor generator comprising a vapor generating section, and separating and circulating means comprising a housing, a shaft rotatable about its axis in the housing, a centrifugal circulating pump on said shaft and rotatable therewith, a vapor and liquid separatorA in the housing, a vapor actuated turbine on said shaft operable by vapor flowing from said separator for driving the shaft, a iluid actuated wheel on said shaft operable as auxiliary driving means for said shaft, a-feed pump for delivering fluid to the circulating pump to be delivered to the vapor generating section, bearings in said housing for said shaft, means for conducting fluid, from the feed pump to said bearings to lubricate the bearings, and means for cooling the fluid delivered to said bearings.

1l. The method of generating and superheating vapor which comprises passing fluid through a vapor generating Zone, introducing vapor and liquid from said zone into a separating zone, separating vapor and liquid by passing the mixture thereof in contact with moving surfaces, utilizing vapor from the separating zone to operate a circulating pump to deliver fluid under pressure to said vapor generating zone, conducting vapor exhausted from said circulating pump to a superheating zone, controlling the quantity of vapor utilized to operate the circulating pump in response to the flow of fluid from the circulating pump to the vapor generating zone, controlling the heat supplied to the vapor generating zone in response to the pressure of vapor discharged from the Superheating zone, and controlling the heat supplied to the superheating zone in response to the temperature of the vapor discharged from the superheating zone.

12. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for controlling the amount of iluid delivered to said path, means for heating the iluid for conversion of liquid to vapor, means for driving said circulating means by vapor flowing from said path, iluid actuated auxiliary driving means tfor said circulating means, fluid feeding means .for

supplying fluid under Ipressure to said auxiliary driving means, and control means responsive t the flowof iluid from said circulating means for controlling the Vflow of fluid to said auxiliary driving means and the flow of vapor to said vapor actuated driving means and operative to diminish the ilow of iluid to said auxiliary driving means and to increase the ilcw of vapor to said vapor actuated driving means upon an increase in the flow of fluid from said circulating means,

13. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for controlling the amount of fluid delivered to said path, means for heating the fluid for conversion of liquid to vapor, means for driving said circulating meansl by vapor flowing from said path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, and control means responsive to the flow of fluid from said circulating means and operative to increase the flow of fluid to the auxiliary driving means and to decrease the flow of vapor to the vapor actuated driving means upon a decrease in the flow cf iiuid from said circulating means thereby to actuate the circulating means by said auxiliary means and to increase the ilow of vapor to said vapor actuated driving means and to decrease the flow of fluid to the auxiliary driving means upon an increase in the flow of fluid from the circulating means thereby to actuate the circulating means by the vapor actuated driving means.

14. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to Vapor, means for driving said circulating means by vapor flowing from said path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, means for controlling the delivery of fluid to the circulating means, and other control means for controlling the flow of iluid to the auxiliary driving 'means in response to the flow of fluid from the circulating means.

` l5. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for driving said circulating means by vapor flowing from said path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying 'fluid under` pressure to said auxiliary driving means, means for controlling the delivery of `fluid to the circulating means in response to the flow of vapor from the path, and other control means for controlling the flow of fluid to the auxiliary driving means in response to the flow of fluid from the circulating means.

16. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the ilud for conversion of liquid to vapor, means for driving said circulating means by vapor flowing from said path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, means for increasing the amount of fluid delivered to the fluid circulating means in response to an increase'in the .flow of vapor from the path, andiother control means for decreasing the 13 iloW of iluid to the auxiliary driving means in response to an increase in the flow of fluid from the circulating means.

17. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, driving means for the circulating means actuated by vapor discharged from said flow path, means for conducting vapor from said path to said driving means, means forming a discharge passage for vapor flowing from said drivingmeans, means forming a by-pass for vapor around said driving means, valve means for controlling both said discharge passage and said by-pass to control the quantity of vapor delivered to said driving means, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to'said auxiliary driving means, means for controlling the delivery of fluid to the circulating means in response to the flov/ of vapor from the path, and other control means for controlling the valve means to vary the quantity of vapor delivered to the driving means and also to vary the flow of fluid to the auxiliary driving means, said control means being responsive to the ow of fluid from the circulating means.

18. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, driving means for the circulating means actuated by vapor discharged from said flow path,

means for conducting vapor from said path to said driving means, means forming a discharge passage for vapor flowing from said driving means, means forming a by-pass for vapor around said driving means, valve means for controlling both said discharge passage and said by-pass to control the quantity of vapor delivered to said driving means, fluid actuated auxiliary driving means for said circulating means, duid feeding means for supplying uid under pressure to said auxiliary driving means, means for increasing the amount of uid delivered to the iluid circulating means in response to an increase in the flow of vapor from the path, and other control means adapted upon an increased flow of fluid from the circulating means to actuate said valve means to permit an increased ilovv of vapor through the discharge passage and thereby to increase the floW of vapor to the driving means and adapted upon an increased flow of fluid from the circulating means to decrease the flow of lluid to the auxiliary driving means.

i9. A vapor generator comprising means forming a uid ilow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for delivering fluid to the circulating means, driving means for the circulating means actuated by vapor discharged from said floW path, means for conducting vapor from said path to said driving means, means forming a discharge passage for vapor flowing from said driving means, means forming a by-pass for vapor around said driving means, valve means for controlling both said discharge passage and said bypass, iluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying uid under pressure to said auxiliary driving means, and control means responsive to the ovv of fluid from said circulating means for controlling the flow of fluid to said auxiliary drivmeans for conducting vapor from said path to said driving means, means forming a discharge passage for vapor flowing from said driving means, means forming a by-pass for vapor around said driving means, valve means for controlling both said discharge passage and said by-pass, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying fluid under pressure to said auxiliary driving means, ilowvcontrolling means for controlling the amount of fluid delivered to the fluid circulating means, and control means responsive to the flow of fluid from said circulating means for varying the llow of uid to said auxiliary driving means and for operating the valve means to vary the flow of vapor delivered to the driving means, the arrangement being such that upon an increase in the flovv of fluid from the circulating means the flow of fluid to said auxiliary driving means is diminished and the valve means is actuated to permit an increased flow of vapor through the discharge passage and a decreased flow of vapor through the by-pass thereby increasing the flow of vapor to the vapor actuated means.

21. A vapor generator comprising a vapor generating section, and separating and circulating means comprising a housing, a circulating pump in the housing, a vapor and liquid separator in the housing, a vapor actuated turbine in the housing for driving the circulating pump, means forming a discharge passage for vapor flowing from said turbine, means forming a Icy-pass for vapor around said turbine, valve means for controlling the amount of vapor flowing through the discharge passage and the by-pass, iluid actuated means in the housing constituting auxiliary means for driving the circulating pump, means for rendering said auxiliary actuating means inoperative and for moving said valve to control the by-pass when the circulating pump is actuated by the vapor turbine and for rendering the auxiliary driving means operative and moving said valve to control the discharge passage when the circulating pump is not actuated by said vapor turbine.

22. The method of generating vapor which comprises delivering fluid to a circulating zone, passing fluid from the circulating zone to a generating zone under pressure, controlling the delivery of iluid to the circulating zone by vapor generated in the generating zone, normally utilizing vapor from the generating zone to develop pressure in the circulating zone, controlling the quantity of vapor utilized to develop pressure in the circulating zone in response to the flow cf fluid from the circulating zone, utilizing fluid under pressure to develop pressure in the circulating zone when the vapor from the generating zone is insuilcient to develop pressure in the circulating zone, and controlling the quantity of fluid under pressure utilized to develop pressure in the circulating zone in response to the floW of fluid from the circulating zone.

23, The method or generating vapor Which comprises passing fluid through a vapor generating zone, utilizing vapor generated inthe generating zone to operate a circulating pump to deliver fluid under pressure to said vapor generating zone, controlling the amount of iluid delivered to the circulating zone, utilizing fluid under pressure to operate said circulating pump when the vapor from the vapor generating zone is insufficient to operate said circulating pump, and controlling loothY the quantity oi vapor utilized and the amount of fluid under pressure utilized to operate the circulating pump in response to the flow of fluid from the circulating pump to the vapor generating zone.

24. The method of generating vapor which comprises passing fluid through a vapor generating zone, utilizing vapor generated in the generating zone to operate a circulating pump to deliver fluid under pressure to said vapor generating zone, controlling the amount of fluid delivered to the circulating pump in response to the vapor generated in the generating zone, utilizing fluid under pressure to operate said Ycirculating pump when the vapor from the vapor generating zone is insuicient to operate said circulating pump, and controlling both the quantity of vapor utilized and the amount of liuid under pressure utilized to operate the circulating pump in response to the flow of fluid from the circulating pump to the vapor generating zone.

25. The method of generating vapor which comprises passing iiuid through a vapor generating zone, introducing vapor and liquid from said zone into a separating zone, separating the vapor and liquid in the separating zone. utilizing vvapor from the separating zone to operate a circulating pump to deliver fluid under pressure to said vapor generating zone, controlling the amount of fluid delivered to the circulating means in response to the vapor generated in the vapor generating zone, utilizing fluid under pressure to operate the circulating pump when the vapor from the vapo;` generating zone is insu'icient to operate the circulating pump, and controlling both the quantity of vapor utilized and the amount of fluid under pressure utilized to operate the circulating pump in response tothe flow of fluid from the circulating pump to the vapor generati ing zone.

26. The method of generating and superheating vapor which comprises passing fluid through a vapor generating zone, utilizing vapor generated in the generating zone to operate a circulating pumpto deliver fluid under pressure to said vapor generating zone, conducting vapor exhausted from said circulating pump to a superheating zone, controlling the amount of fluid delivered to the circulating means in response to the flow of vapor from the circulating pump to the superheating zone, utilizing fluid under pressure to operate the circulating pump when the flow of vapor to the superheating zone is insumcient to operate the circulating pump, controlling both the quantity of vapor utilized and the amount of fluid under pressure utilized to operate the circulating pump in response to the flow of fluid from the circulating pump to the vapor generating zone, controlling the heat supplied to the vapol` generating zone in response to the pressure of vapor discharged from the superheating zone, and controlling the heat supplied to the superheating zone in response to the temperature of the vapor discharged from the superheating l zone.

27. A vapor generator comprising tubular means forming a fluid flow path, circulating means for delivering iiuid to said path under pressure, means for heating the fluid in said path for conversion of liquid to vapor, a pump for delivering fluid to the circulating means, and driving means for the circulating means actuated loy fluid discharged by said pump, the discharge of the driving means 1being connected to the intake of said pump.

28. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for actuating said circulating means by'vapor flowing from said path, auxiliary actuating means ior said circulating means, and control means responsive to the flow of fluid to said path for rendering the auxiliary driving means inoperative when the vapor actuating means is operative.

29. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to Vapor, means for actuating said circulating means by vapor flowing from said path, auxiliary actuating means for said circulating means, and control means responsive to the lovvI of fluid to said path for rendering the auxiliary actuating means inoperative when the circulating means is actuated by the vapor actuating means and rendering the auxiliary actuating means operative when the circulating'means is not actuated by said vapor actuated means.

30. Av vapor generator comp-rising means forming a fluid flow path, circulating means for delivering iluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for driving said circulating means by vapor flowing from said path, auxiliary driving means for said circulating means, and control means to control the operation of said auxiliary driving means in response to the floW of fluid to said path. y

31. A vapor generator comprising means forming a fluid flow path, circulating means for de livering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for actuating said circulating means -by vapor flowing from said path, fluid driven auxiliary actuating means for said circulating means, and control means responsive to the flow of fluid to said path for rendering said fluid driven auxiliary actuating means inoperative Whe-n the vapor actuating means is operative.

32. A vapor generator comprising means forming a fluid flow path, circulating means for delivering fluid to said path under pressure, means for heating the fluid for conversion of liquid to vapor, means for actuating said circulating means by vapor flowing from said path, fluid driven auxiliary actuating means for said circulating means, and control means for rendering said fluid driven auxiliary actuating means inoperative when the circulating means is actuated by the vapor actuating means and for rendering said auxiliary actuating means operative when the circulating means is not actuated by the vapor actuating means, and fluid feeding means for supplying fluid under pressure to said auxiliary actuating means.

33.v A vapor generato;- comprising means forming a uid flow path, circulating means for deliveringfluidto said pathunder pressure, means for heating the iiuid for conversion of liquid to vapor,

means for actuating said circulating means by vapor, fluid driven auxiliary actuating means'for Asaid circulating means, control means for renderable vapor and liquid separating means in the path of the vapor flowing from said first-mem tioned separator to the vapor actuated means.

34. A vapor generator comprising means forming a fluid iiovv path, circulating means for d'elivering uid to said path under pressure, means for heating the iiuidfor conversion of liquid to vapor, means for actuatingsaid circulating means .by vapor, fluid drivenauxiliary actuating means for said circulating means, control means for rendering said fluiddriven auxiliary actuating means inoperative when the circulating means is actuated by. theA vapor actuating means and for rendering said auxiliary actuating means operative when the circulating means is not actuated by the vapor actuating means, means for delivering vapor and liquid from said flow path to the means for actuating said circulating means by vapor, a separator in the path of ow of vapor from said flow path to the vapor actuated means, and movable vapor and liquid separating means in the path of the vapor owing from said rstmentioned separator to the vapor actuated means,

the movable separating means being operatively connected to said circulating means and actuated therewith.

35. A vapor` generator comprising means forming a fluid iiow path, circulating means for delivering fluid into said path under pressure, means for heating the fluid for conversion of liquid to vapor, vapor actuated driving means for driving said circulating means by vapor iiowing from said flow path, fluid actuated auxiliary driving means for said circulating means, fluid feeding means for supplying iiuid under pressure to said auxiliary driving means, and control means responsive to the flow of fluid from said circulating means for controlling the flow of fluid to said auxiliary driving means and the flow of vapor to said vapor actuated driving means to diminish the flow of fluid to said auxiliary driving means and to increase the iioW of vapor to said vapor actuated driving means upon an increase in flo-W of fluid from said circulating means.

36. The method of generating vapor which comprises delivering fluid to a circulating zone, passing fluid from the circulating zone to a generating zone under pressure, controlling the delivery of fluid to the circulating Zone by vapor generated in the generating zone, normally utilizing vapor from the generating zone to develop pressure in the circulating zone, utilizing fluid under pressure to develop pressure in the circulating Zone when the vapor from the generating zone is insufficient to develop pressure in the circulating zone, and controlling the quantity of fluid under pressure utilized to develop pressure in the circulating zone in response to the flow of iiuid from the circulating zone.

37. A vapor` generator comprising a vapor generating section, a superheating section, means for firing-the vapor generating and superheating sections, circulating means, means for conducting fluid to the circulating means,- conduit means for conducting fluid under pressure from the circulating means to the vapor generating section, vapor actuating means for actuating the circulating means, means for conducting vapor from the vapor generating section to the vapor actuating means, uid actuated auxiliary driving means for said circulating means, means for conducting fluid under pressure to said auxiliary driving means, controlmeans to control the flovvof fluid to said auxiliary driving means in response to the flow of fluid to the vapor generating section, and conduit means for conducting vapor from the vapor actuatedV meanstothe superheating section. Y

38. A vapor generator comprising a vapor gen erating section, a superheating section, means for ring the vaporgenerating and superheating sections, circulatingv means, means for conducting fluid to the circulating means, conduit means for conducting fluid under pressure from'the circulating means to the vapor `generating section, vapor actuating means for actuating the circulating means, means for conducting vapor from the vapor generating section to the vapor actuating means,Y fluid actuated .auxiliary driving means for said circulating means, means for conducting fluid under pressure to said auxiliary driving means, contro1 means for rendering the auxiliary actuating means inoperative when the circulating means is actuated by the vapor actuating means and rendering the auxiliary actuating means operative when the circulating means is not actuated by said vapor actuated means, and conduit means for conducting vapor from the vapor actuating means to the superheating section.

39. A vapor` generator comprising a vapor generating section, a superheating section, means for firing the vapor generating and superheating sections, separating and circulating means comprising a housing, a circulating pump in the housing, a vapor and liquid separator in the housing, a vapor actuated turbine in the housing for driving the circulating pump, iuid actuated means in the housing constituting auxiliary means for driving the circulating pump, control means for rendering the uid actuated means inoperative when the circulating pump is actuated by the vapor actuated turbine and for rendering the fluid actuated means operative when the circulating pump is not actuated by said vapor actuated turbine, and means for conducting vapor from the vapor turbine to the superheating section.

40. A vapor generator comprising tubular means forming a fluid iioW path, means for heating fluid in said path for conversion of the fluid to vapor, circulating means for delivering fluid to said path under pressure having an inlet and a discharge, means for delivering feed fluid to the inlet of the circulating means prior to introduction of the fluid into said flow path, means for delivering feed iiuid from the discharge of the circulating means to said flow path, and driving means for the circulating means actuated by uid discharged by the means for delivering feed fluid to the circulating means, the discharge of the driving means being unconnected directly With the inlet of the circulating means.

41. A. vapor generator comprising tubular means forming a uid iioW path having an inlet through which feed fluid enters the path and an outlet through which vapor is discharged from the path, circulating means for delivering uid to said path under pressure having an inlet and discharge, conduit means connecting the inlet of said path and the discharge of thecirculating means; means for'heating the fluid in said path for conversion of liquid to vapor, means for discharging feed fluid under pressure, means Vfor conducting part of the feed fluid discharged from said feed fluid discharging means to the inlet of the'circulating means prior to the introduction ofthe feed fluid into the 110W path, fluid actuated driving means for the'circulating means, and means for conducting to the driving means another part of the iiuid discharged yfrom said feed fluid discharging means to `actuate the driving'means, the discharge of theV driving means being unconnected directly with the inlet 4of the circulating means..v Y l 142( The method of generating vapor which comprises delivering fluid to la`circulating zone, passing fluid from the circulating'zon to a generating zone under pressure, controlling the delivery of fluid to the `circulating fzone, normalll7 utilizing vapor from the generating lzone to develope pressure'in' the circulating zonepcontrolling the quantity of vapor utilized to develop pressure in the circulating zone in response 'to the now of iiud from 'the circulating zone, utilizing fluid under pressure to develop pressure in the circulating zone when the vapor'from the generating zone is insufncient to develop pressure in the circulating zone, and controllingthe quantity of fluid under pressure utilized 'to' develop lpressure in the circulating zone in response'to the ow of fluid from the circulating zone.

43. The method of generating vapor which comprises delivering fluid under pressure to a generating zone, normally controlling the delivery of uid to the generating zone by the ow of vapor generated in said zone, initially controllingthe deliver;7 of fluid tothe generating zone by the flow of other fluid under pressure, decreasing the flow of other nuid under pressure in response to an increased ow of the first-mentioned iiuid to the vapor generating zone until the vapor generatedin the vapor vgeneral-,ing zone is suiiicient .to control the delivery of fluid to the generating zone, discharging said other fluid from direct flow to said generating zone after use of said other fluid 'for initially controlling delivery of the first-mentioned iiuid, and thereafter normally controlling the delivery ofsaid first-mentioned uid to said vapor generating zone.

' MARTIN FRISGH. 

